Bionic Design Of Flexible Electronic Skin Temperature Sensation Based On Thermoelectric Effect

Electronic skin is a functional device that simulates human skin perception of external pressure,light,temperature and humidity through structural and functional design,and is an important medium for human-computer interaction.Temperature is an important physical quantity in nature.Researchers have studied the temperature sensing of electronic skin,while few have systematically studied the temperature perception of artificial limbs.Current prosthetics are capable of sensitive mechanical operation,but lack comfort due to their material and structural properties.In order to improve the acceptability and practicability of the artificial limb,this paper proposes a biomimetic design of electronic skin temperature on the surface of the artificial limb,so as to solve the problem of hard and cold surface of the artificial limb.Based on the above background,this paper carries out the thermal bionic design of the electroni c skin of the prosthesis,and realizes the temperature sensing and temperature regulation of the prosthesis for complex environments.A thermocouple based on a two-dimensional spring structure was prepared as a temperature sensor on the surface of the prosthesis.A two-dimensional spring structure with different curvature radii was designed,and then a mask of the corresponding shape was machined.Finally,the temperature array was prepared on the flexible substrate by magnetron sputtering,and the flexible thermocouple temperature sensor was prepared by using polydimethylsiloxane(PDMS)as the packaging material.In order to improve the response speed and sensitivity of thermocouple,copper wire with high thermal conductivity was connected to the temperature measuring point as bionic cilia,referring to the cilia structure of human body.The experimental results show that the bionic thermocouple of the flexible cilia can identify the temperature change of the heat source at 0.02 ℃,and its sensitive is 41.25 μV/K,and the temperature sensor array has a good temperature response signal,and can distinguish the temperature distribution of the environment or objects.A temperature-regulated device based on a flexible thermoelectric device is designed,which consists of a phase change thermal reservoir at the top and a flexible thermoelectric device at the bottom.According to the body perception of temperature,paraffin with phase change point of 35 ℃ is selected to provide overheating protection for temperature control devices.During paraffin liquefaction,the instability of the flexible structure appears due to the uneven cooling rate.In order to meet the requirements of flexibility and structural stability of electronic skin,a composite flexible structure composed of foam and paraffin is proposed in this paper.In this paper,the effects of phase change layer thickness,ambient temperature,wind speed and active temperature regulation on the performance of temperature control devices are systematically studied.The experimental results show that the temperature-regulated device combining active mode and passive mode can make the surface temperature of the device in the comfort zone,and its temperature control curve is consistent with the trend of the body temperature control curve,which is suitable for the surface temperature control of the prosthesis.